Conventionally, small cylindrical medical bottles such as ampules, vials or the like are successively filled with a medical liquid in a clean room (aseptic room) by a filing machine, encased in cases and then brought to the exterior of the clean room (aseptic room).
In the production of such bottled medical liquid, it is a key for the guarantee of the quality to enhance the cleanness (asepsis) during filling. To this end, it is most convenient to minimize the volume of the clean room, while serving as much as possible the number of workers and machines in the clean room, so as to enable the bottles stuffed with the liquid to be directly conveyed to the exterior of the clean room without any manual labor.
To cope with such a demand, the applicant has proposed a belt type transfer apparatus of the type which is disclosed in Japanese Patent Laid-Open No. 62-167120.
This belt type transfer apparatus has, as shown in FIG. 9, a row of rollers 1 extending in the direction of the transfer or convey and another row of rollers 2 arranged at predetermined spacing from the first row. Belts 3 are stretched between rollers 1, 1 and also between rollers 2, 2 so that two rows of groups of belts are formed in pairs, the rollers 1 and the rollers 2 are driven by a driving system at the same speed so that objects 4 such as ampules are pinched between and transferred by the belts 3.
An example of this type of transfer apparatus will be described with reference to FIG. 10. In this belt type transfer apparatus, two rows of rollers 1 and 2 are arranged to define a path which first extends horizontally and then vertically or a path in which the objects which are being transferred are progressively turned sideways and then upright. The belts 3 are stretched over these rollers and the rollers 1 and 2 are driven at the same speed by a driving unit such as a motor which is disposed at the outlet end of the path, whereby the objects are conveyed from the clean room 6 to the exterior 8 via the intermediate chamber 7. This belt type transfer apparatus enables the objects 4 such as ampules to be safely and stably conveyed to a destined position over a long distance without requiring any specific attention to timing of the transfer, thus contributing to enhancement of the asepsis and realization of unmanned operation. This transfer system can transfer the objects 4 in any desired direction over a long distance. For changing the transfer direction, a pair of rollers 1 and 2 are provided at a corner or region where the direction is to be changed and belts 3, 3 are stretched to define the new direction of the transfer path. The distance between the rollers 1 and 2 must be maintained constant in conformity with the size of the object 4 to be transferred. This requires that the distance between the pair of the rollers 1 and 2 be delicately adjusted in accordance with the size of the object 4 to be transferred. If this adjustment is failed, troubles are caused such as collapse of the object 4 due to too narrow gap between the rollers or dropping or throwing of the object 4 due to too large gap between the rollers.
In addition, readjustment of the gap between the rollers is necessary each time the type of the object 4 to be transferred is changed, in conformity with the size of the new type of the object 4. Thus, the known transfer apparatus could not be used for a plurality of types of objects having different sizes.
Another problem encountered with this known transfer apparatus is that, when the objects 4 are transferred at high speed, it is not easy to receive and encase the objects 4 which jump off the outlet of the transfer apparatus. Deceleration is necessary to obviate this problem and to ensure a smooth delivery of the objects 4 to a next step. Problems are caused also when a plurality of driving motors are used for a long-distance transfer. In such a case, adjacent rollers may be driven at different speeds, causing mechanical overload between the rollers and the belts, resulting in damages of the rollers 1, 2 and the belts 3 or rubbing of the rollers and belts to generate dust which causes contamination. It is therefore necessary to smoothly absorb any difference in the rotation speed between adjacent rollers at selected region of the transfer apparatus where any difference of roller speed takes place.
The present inventors have discovered, as a result of an intense study, that a belt type transfer apparatus capable of changing transfer direction regardless of the size of the object without requiring any readjustment is obtainable by adopting a specific arrangement of rollers and a specific manner of setting the belts. The inventors also have found that any difference in the rotation speed of the rollers due to a change in the transfer speed can be absorbed smoothly by a specific construction of the roller.
An object of the present invention is to provide a belt type transfer apparatus which can smoothly change the transfer direction and which can transfer different types of objects of different diameters without causing breakage of the bottle.
Another object of the present invention is to provide sectional roller for use in a belt type transfer apparatus,capable of absorbing any difference in the rotation speed between adjacent rollers.